|
|
|
| Reduction of Cr (Ⅵ) in water under the condition of photon and nano-iron |
|
|
|
|
Abstract Nanoscale zero-valent iron (NZVI) was synthesized in aqueous solutions by reduction of Fe3+ with NaBH4. The crystal structure and morphology features of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), respectively. The reduction rate of the Cr(Ⅵ) was investigated to understand the effect of irradiation of medium pressure mercury lamp on reduction of Cr(Ⅵ) with NZVI, and the effects of irradiation under the conditions of different dosages and pH values. The experimental result showed that nano iron has high reaction activity, and its particle size was about 7.6nm and spontaneously flammable in air. With the initial Cr(Ⅵ) concentration of 20mg/L, pH=7±0.5 and a temperature of 25℃ and NZVI dosage of 0.1g, the reduction rate of Cr(Ⅵ) reached 62.3% under the action of irradiation for 60 minutes while it was only 27.6% without irradiation. The irradiation process played a role in promoting the reduction efficiency of Cr(Ⅵ) at less dosage of NZVI but the effect of reducing action was greater than that of irradiation when the dosage of NZVI was enough. The pH value had a more obvious effect than the irradiation on removal rate of Cr(Ⅵ). The charge in nano iron may be oscillated by the irradiation of ultraviolet light and transferd to the adsorbed molecular, which explained the irradiation promoted reduction of nano iron Cr (VI).
|
|
Received: 05 January 2014
|
|
|
|
|
|
|
